Climate Model Ensembles to Evaluate the Impact of Climate Change on Yield and Water Use Efficiency of Different Dry-Season Rice Varieties Cultivated under Conventional and Alternative Wetting and Drying (AWD) Conditions

Abstract To address water scarcity, enhancing water use efficiency, especially for dry-season rice cultivation, is crucial, especially in the context of climate change. Alternative Wetting and Drying (AWD) irrigation has been effective in conserving water in various regions. However, there is a lack of research on the feasibility of AWD as a potential technique for climate adaptation. This is the first-ever attempt to utilize the AquaCrop model in evaluating the effects of climate change on different rice varieties cultivated under AWD irrigation, employing climate model ensembles for the mid-century period (2041–2070) based on the most recent emission scenarios within the Coupled Model Intercomparison Project Phase 6 (CMIP6). Field experiments were conducted in 2023 to get the input for calibrating and validating the AquaCrop. We adopted SSP3-7.0 and SSP5-8.5 to represent medium and highest greenhouse gas emissions. For each scenario, we applied 4 different GCMs. The ensemble-model projection indicated that rice grown longer than 94 DAT is more prone to damage in the future. The ensemble-model projection indicated that rice grown longer than 94 DAT is more prone to damage in the future. In our case, grain yields of CAR15 and Sen Kra Ob were reduced and more than 60–70% of these two varieties were damaged under SSP3-7.0 scenarios, and between 33% − 50% were damaged under SSP5-8.5. OM5451 and Sen Pidor are the suitable varieties selected to adapt to climate change. In terms of WUE, AWD is a promising technique to save water in the future.